This invention generally relates to vehicle transmissions. More particularly, this invention relates to a transmission system having an automated clutch actuator that opens the clutch under selected conditions to eliminate gear rattle within the transmission.
A variety of vehicle transmissions are available currently in the market. Some transmissions are automated and do not require operator input other than selecting, for example, reverse or drive. Other transmissions are manual and require manual operation of a gear shift lever to manually move transmission components into selected gear ratios. Manual transmissions typically require manual actuation of a clutch pedal to eliminate the connection between an engine output shaft and an input shaft of the transmission. Manual clutch pedal actuation is typically required each time that a shift in gears is desired.
More recently, suppliers and vehicle manufactures have been attempting to simplify the operation of manual transmissions. Even with such improvements, those skilled in the art are always striving to make transmission systems better and more efficient. One problem that has not been addressed is commonly known as neutral gear rattle. This typically occurs when a vehicle, such as a heavy duty truck, is not moving so that the engine is at an idle speed. When the transmission is in neutral and the engine is at idle speed, there typically is enough rotation imparted to the transmission components so that a rattling of the gears occurs. This condition is undesirable because it generates noise and causes unnecessary contact between the various components of the vehicle transmission.
It is desirable to eliminate the neutral gear idle rattle problem. This invention addresses that need by providing an automated clutch actuator and a control strategy in order to automatically eliminate the possibility for the undesirable gear rattle.
Automated clutch actuators are known in the art, such as disclosed in U.S. Pat. No. 4,981,202. While automated clutch actuators are known, they have not been utilized in a manner that is effective to eliminate neutral gear idle rattle as is provided by this invention.